Air conditioning apparatus



March 18, 1941 c ASHLEY 2,235,004

AIR CONDITIONiNG APPARATUS Filed April 6, 1938 i l l i l l I INVENTOR. CAELYLE' M. 115/115! A TTORNEYI.

Wuteriied Mar. 18 1941 UNITED STATES 2,235,00 l AIR CONDITIONING APPARATUS Carlyle M. Ashley, Syracuse, N. Y., assignor to Carrier Corporation, Syracuse, N. Y., a corporation of Delaware Application April 6, 1938, Serial No. 200,494

2 Claims.

This invention relates to air conditioning. The general object of the invention is to provide an air conditioning apparatus for controlling the moisture content of air or other gas which is w to be conditioned.

in the conditioning of enclosures occupied by persons whose comfort and health are primary considerations, it is necessary that a quantity of outdoor air be supplied to such enclosures at all m timeain order to meet. the ventilation requirements of the occupants. Under summer operatirie conditions in most localities the fresh air thus supplied is usually hot and humid and hence requires reduction of its moisture content inorder it that it may be used to create'and maintain comlortable atmospheric conditions within the enclosures. Also, in cooling enclosures for comfort, it is common practice to recirculate a portion of theair withdrawn from the enclosure. In concu ventional installations the quantity of air thus recirculated may be of the order of four or five times the quantity of fresh air introduced into the enclosure. In its circulation through the occupied enclosure, the conditioned air is subject to a subco stantial increase in moisture content, due to the evaporation of water from the bodies of the occupunts, as is well understood. Thus, in order that it may be suitably prepared for resupply to the enclosure, this air withdrawn from the enclosure W lor recirculation must also have its moisture content reduced in order that comfortable atmospheric conditions may be created and maintained in the enclosure.

fiimilarly, in certain industrial applications of as air conditioning it is necessary to remove moisture lrom the air in order to provide desired atmospheric conditions.

Reduction of the moisture content of the air may be accomplished broadly by either of two 3 methods, namely, dehumidiflcation and dehydras tlou. When the air is dehumidified, it is subjected to heat exchange with acooling medium or refrigerant which reduces the dry bulb temperature below the original dewpoint of the air, thus prey; clpitating moisture from the air. This method has the disadvantage that the cooling process and the process of moisture reduction are definitely and inseparably interrelated, thus creating control problems. Further, the air which has been so dehumidified is necessarily at a relatively low dry bulb temperature and hence, in most applications, must be reheated before it may be introduced into the enclosure to be conditioned.

- An object of the present invention is to provide u an apparatus and method for reducing the moisture content of air to be conditioned by dehydration, without cooling the air. Thus, the necessity for reheating is eliminated. Also, the process of moisture reduction is divorced from the process of controlling the temperature, so that these may 5 be controlled independently. Accordingly, control problems are simplified.

Another object of the present invention is to provide an improved apparatus for and method of conditioning air in which a liquid absorber is used. This process is based upon the fact that solutions of hygroscopic salts as, for example, lithium chloride and calcium chloride, when they are brought in contact with air having a higher vapor pressure, will absorb moisture from the air with which they contact. As such a solution absorbs moisture from the air, due to the difference in the respective vapor pressures of the solution and of the air, the solution is diluted so that its vapor pressure is increased and its capacity for absorbing water from the air is decreased. In order that the solution may be kept at the proper strength, heat must be supplied to the solution in sufllcient amount to evaporate excess moisture from the solution.

Accordingly, a feature or the invention resides in the provision of means for evaporating moisture from an absorber solution, thus to increase the density and vapor pressure of the solution,

whereby it may function effectively to absorb -tration and supplying concentrated solution to be circulated in contact with said air.

Other objects and features of the invention will become more apparent from the following description to be read in connection with the accompanying drawing which diagrammatically illustrates one embodiment of the invention. J

Referring to the drawing, the numeral 5 designates generally a casing through which there is circulated air to be conditioned. The casing 5 is provided with a sump 6 adapted to receive and contain a suitable absorber solution such as lithium chloride, calcium chloride or the like. A pump 1, driven bya motor or the like, 8, serves to withdraw absorber solution from the sump 6 and supply it to thespray device 9 through supply pipe lfl. The lithium chloride or other ab-. sorbet solution sprayed from spray device 9 passes of the solution and to prepare it for a repetition of its moisture absorbing function. The regenerating chamber II is provided with an outlet opening l3 which permits the escape of water evaporated from the solution within the container II. If desired, a fan i4 may be utilized in the outlet opening to assist the withdrawal of vapor from the chamber I I, and an inlet opening I5 may be provided for supplying air to the regenerating chamber The air thus circulated through the regenerating chamber picks up the moisture evaporated from the solution contained in the regenerating chamber and removes itfrom the system. If desired, the inlet opening l5 may be sufliciently small or sufliciently restricted in any suitable manner (as, for example, by dampers) so that when the fan I 4 is operative, the pressure within the regenerating chamber will be lowered somewhat below atmospheric pressure.

In this way, the boiling point of the water in the absorber solution will be lowered and the evaporation oi such moisture facilitated Within the regenerating chamber I I there is provided a density-responsive control device I6, such as a hydrometer, which serves to open valve 11 in fuel supply line is whenever the density of the solution in chamber ll falls below a predetermined point. Thus, when concentration of the fluid in chamber II is required, gas will be supplied to the burner device l2 to supply the heat necessary to eflect this result.

Device I6 also controls valve I!) to regulate the emission of regenerated solution to interchanger 20a. So long as the solution in chamber Ii is below a desired density, device l6 will maintain valve Ill closed, and valve I! open in order to regenerate the solutionj When the solution has attained a predetermined density, valve l'l will be closed to interrupt the supply of fuel for regeneration and valve i9 will be opened.

Thus, whenever the density of the solution in chamber II is sufficiently high so that such solution may be eflectively used for air conditioning purposes, the control device l6 operates to open tank2l.

valve IS in line 20, thus to permit solution to flow from regenerating chamber ll into cooling Preferably, line 20 is routed through an interchanger 20a where the solution passing from the regenerating chamber II is subjected to heat exchange with the solution passing to chamber II for regeneration. Thus, the solution to be regenerated is preheated prior to its entry into the regenerating chamber H, and the regenerated solution to be cooled is precobled before 'its delivery to the cooling tank 2|. Tank 2| is preferably at a lower level than regenerating chamber 'Il so that the solution may flow to the cooling tank 2| by gravity. Within the cooling tank 2| is positioned a cooling device 22 01' any suiable design. Preferably, this constitutes a multiple pass coil provided with extended surface, such as spiral or plate finning. Cooling medium,

such as cold water or the like, from any suita le source is supplied to the cooling device 22 through main supply line 23 and branch supply line 23a.

ditioner. n Whenever the density falls below a predetermined point, hydrometer 26 serves to open valve 21 in line 28, thus to supply to the sump 6 of the air conditioning unit absorber solution having a desired temperature and concentration. Whenever the valve 21 is opened by the hydrometer 26, the latter also serves to open valve 29 in branch line Illa. Thus, as fresh solution is supplied to the sump 6, diluted absorber solution is withdrawn therefrom and returned to the regenerator ii for reconcentration. If desired, the valves 21 and 28 may be 01 the type which, whenever they are opened, remain open for a predetermined period of time and then automatically close. If the valves are of this type, then the valves will be opened a suificient number of times to insure the return of the absorber solution in the sump 6 to a predetermined density.

Since the dehydration of the air by the action of the absorber solutionserves to release the latent heat of vaporization oi! the moisture thus precipitated, there is a tendency for the sensible heat of the dehydrated air to be increased. To counteract the rise in dry bulb temperature, which would thus occur, there is preferably provided in the path of the dehydrated air a cooling device 30, such as acooling coil provided with extion which is maintainedin the sump 6, and by the effective operating temperature of the solution contacting the air.

If desired, thecoil 30 'may be positioned within the casing 5 at a point beyond that at which the air being conditioned is contacted by spray from header 9. However, it is preferred to place the coil 30 beneath the spray header 9, since this ma-- terially increases the operating efficiency oi the apparatus. The sprayed solution falling upon the coil 30 serves to wet the same and thereby to increase the heat transfer through the walls 01' the coil. Further, the coil thus provides a,surface over -which the absorber solution spreads in the form oithin fllm whichincreases the eflective dehydration of the air passing in contact there-' with since, in the aggre ate, this film provides a larger-contact areaithan it the liquid from which it is formed-were precipitated as a spray. Further the cooling of the sprayed solution by its contact/with the coils in this manner further increases the moisture-absorbing effectiveness at the sprayed solution. p

It will be noted that the coils 30 and 22 are connected in parallel to the supply line 23 and the discharge line 32. Thus, the operation of these coils is entirely separate and distinct. A series connection may be used if desired.

If desired, the hydrometer 26 may serve to control only valve 29, instead of both valves 21 and 29. In such case, a desired liquid level may be maintained in sump 6 by controlling valve 21 by a suitable float device within the sump which may be of any well-known type.

Since-many changes may be made in the invention without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative only and not in a limiting sense, applicant limiting himself only as indicated in the appended claims.

I claim:

1. In combination, for air conditioning an enclosure, a conditioning chamber, an air inlet and an air outlet for the conditioning chamber, spray apparatus within the chamber for distributing an absorber solution, a cooling coil within the chamber over whichthe solution is sprayed, a sump at the bottom of the chamber, a pump for supplying solution from the sump to the spray apparatus, means simultaneously operative for admitting water to said cooling coil when said pump becomes operative, a solution supply chamber and simultaneously removing 2!. correspond ing volume of diluted solution from the conditioninc chamber to the regenerator chamber, means connecting the solution interchanger chamber with the solution supply chamber and the regenerator chamber whereby regenerated solution will flow from the regenerator chamber through the interchanger chamber into the solution sup- N ly chamber, means connecting the interchange:

chamber with the conditioning chamber and the V regenerator chamber whereby solution from the conditioning chamber will flow through the interchanger chamber to the regenerator chamber, and means for routing regenerated uncooled solution from the regenerator chamber and returning diluted solution from the conditioning chamber in interchange relationship through said interchanger chamber.

2. In combination, for air conditioning an enclosure, a conditioning chamber, an air inlet and an air outlet for the conditioning chamber, spray apparatus within the chamber for distributing an absorber solution, a coolin coil within the chamber over which the solution is sprayed, a

sump at the bottom of the chamber, a pump for supplying solution from the sump to the spray apparatus, means simultaneously operative for admitting water to said cooling coil when said pump becomes operative, a solution supply chamber operatively associated with the conditioning chamber, a cooling coil in said solution supply chamber, means for controlling the action of said last mentioned cooling coil to govern the tem perature of solution in the solution supply chamber, a solution interchanger chamber, a regenerator chamber operatively associated with the interchanger chamber, means operative? responsive to the condition of the solution in the conditioning chamber for admitting a measured volume of cooled, regenerated solution to the conditioning chamber from the solution supply chamber and simultaneously removing a corresponding volume of diluted solution from the conditioning chamher to the regenerator chamber, means connect ing the solution interchanger chamber with the solution supply chamber and the regencrator chamber whereby regenerated solution will flow from the regenc'rator chamber through the interchanger chamber into the solution supply chamber, means connecting the interchanger chamber with the conditioning chamber and the regenerator chamber whereby solution irom the conditioning chamber will flow through the interchanger chamber to the regenerator chamber, means for routin regenerated uncooled solution from the regenerator chamber and returning diluted solution from the conditioning chamber in interchange relationship through said inter changer chamber, and means for controlling the pressure in the regenerator chamber.

l CARLYLE M, m. 

